gpio: pca953x: Override IRQ for one of the expanders on Galileo Gen 2

ACPI table on Intel Galileo Gen 2 has wrong pin number for IRQ resource
of one of the I²C GPIO expanders. Since we know what that number is and
luckily have GPIO bases fixed for SoC's controllers, we may use a simple
DMI quirk to match the platform and retrieve GpioInt() pin on it for
the expander in question.

Mika suggested the way to avoid a quirk in the GPIO ACPI library and
here is the second, almost rewritten version of it.

Fixes: f32517bf1ae0 ("gpio: pca953x: support ACPI devices found on Galileo Gen2")
Depends-on: 25e3ef894eef ("gpio: acpi: Split out acpi_gpio_get_irq_resource() helper")
Suggested-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Reviewed-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>

diff --git a/drivers/gpio/gpio-pca953x.c b/drivers/gpio/gpio-pca953x.c
index afe7863..4d3157d 100644 (file)
--- a/drivers/gpio/gpio-pca953x.c
+++ b/drivers/gpio/gpio-pca953x.c
@@ -107,6 +107,79 @@ static const struct i2c_device_id pca953x_id[] = {
 };
 MODULE_DEVICE_TABLE(i2c, pca953x_id);
 
+#ifdef CONFIG_GPIO_PCA953X_IRQ
+
+#include <linux/dmi.h>
+#include <linux/gpio.h>
+#include <linux/list.h>
+
+static const struct dmi_system_id pca953x_dmi_acpi_irq_info[] = {
+       {
+               /*
+                * On Intel Galileo Gen 2 board the IRQ pin of one of
+                * the I²C GPIO expanders, which has GpioInt() resource,
+                * is provided as an absolute number instead of being
+                * relative. Since first controller (gpio-sch.c) and
+                * second (gpio-dwapb.c) are at the fixed bases, we may
+                * safely refer to the number in the global space to get
+                * an IRQ out of it.
+                */
+               .matches = {
+                       DMI_EXACT_MATCH(DMI_BOARD_NAME, "GalileoGen2"),
+               },
+       },
+       {}
+};
+
+#ifdef CONFIG_ACPI
+static int pca953x_acpi_get_pin(struct acpi_resource *ares, void *data)
+{
+       struct acpi_resource_gpio *agpio;
+       int *pin = data;
+
+       if (acpi_gpio_get_irq_resource(ares, &agpio))
+               *pin = agpio->pin_table[0];
+       return 1;
+}
+
+static int pca953x_acpi_find_pin(struct device *dev)
+{
+       struct acpi_device *adev = ACPI_COMPANION(dev);
+       int pin = -ENOENT, ret;
+       LIST_HEAD(r);
+
+       ret = acpi_dev_get_resources(adev, &r, pca953x_acpi_get_pin, &pin);
+       acpi_dev_free_resource_list(&r);
+       if (ret < 0)
+               return ret;
+
+       return pin;
+}
+#else
+static inline int pca953x_acpi_find_pin(struct device *dev) { return -ENXIO; }
+#endif
+
+static int pca953x_acpi_get_irq(struct device *dev)
+{
+       int pin, ret;
+
+       pin = pca953x_acpi_find_pin(dev);
+       if (pin < 0)
+               return pin;
+
+       dev_info(dev, "Applying ACPI interrupt quirk (GPIO %d)\n", pin);
+
+       if (!gpio_is_valid(pin))
+               return -EINVAL;
+
+       ret = gpio_request(pin, "pca953x interrupt");
+       if (ret)
+               return ret;
+
+       return gpio_to_irq(pin);
+}
+#endif
+
 static const struct acpi_device_id pca953x_acpi_ids[] = {
        { "INT3491", 16 | PCA953X_TYPE | PCA_LATCH_INT, },
        { }
@@ -754,6 +827,12 @@ static int pca953x_irq_setup(struct pca953x_chip *chip, int irq_base)
        DECLARE_BITMAP(irq_stat, MAX_LINE);
        int ret;
 
+       if (dmi_first_match(pca953x_dmi_acpi_irq_info)) {
+               ret = pca953x_acpi_get_irq(&client->dev);
+               if (ret > 0)
+                       client->irq = ret;
+       }
+
        if (!client->irq)
                return 0;